By Scout Nelson
Spring weather in Minnesota can be difficult for gardeners to understand. Warm days may suggest it is time to plant, but cold nights and cool soil can still create problems. Because of this, gardeners should not rely only on the calendar. Good planting decisions depend more on soil temperature, air temperature, and the type of crop being grown.
Minnesota has a short growing season and large temperature changes in spring. Southern parts of the state often warm earlier, while northern areas stay colder longer and face frost risk later into the season. This means gardeners in the south may plant one or two weeks earlier than those in the north. Raised beds and black plastic can also help warm the soil faster.
Knowing the local frost-free date is very important. In southern Minnesota, the average last frost often comes in early May. In northern areas, it may not arrive until late May or even early June. A few warm days in April can be misleading, so checking weather forecasts remains important.
Soil temperature plays a major role in healthy seed germination and root growth. Cold soil can slow plant growth and increase the chance of rot and disease. Gardeners can use a soil thermometer placed about four inches deep for better reading. Early cool-season crops grow well when soil temperatures reach 40 to 50 degrees Fahrenheit. These crops include peas, spinach, lettuce, radishes, carrots, beets, kale, Swiss chard, onions, and potatoes.
Air temperature also matters because it affects plant survival. Tender plants can be damaged by a light frost and killed by a hard frost. Frost cloths or row covers can help protect early plantings when temperatures fall.
Moderately warm-season crops grow best when soil temperatures reach 55 to 60 degrees. Heat-loving crops should be planted only when soil reaches 65 degrees or more, and frost danger has ended. These include tomatoes, peppers, cucumbers, squash, beans, corn, basil, and melons. In Minnesota, smart timing leads to healthier plants and better harvests.
Photo Credit: gettyimages-joshua-resnick
Categories: Minnesota, Crops, Harvesting, Weather